<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://unpkg.com/vue@3"></script>

</head>
<body>
  <div id="root">{{message}}</div>
</body>
<script>
  const app = Vue.createApp({
    data() {
      return {
        message: "hello world"
      }
    },
    template: `<div> {{message}} </div>`
  });

  const vm = app.mount("#root");
  console.log(vm.message);

</script>
</html>